Dial *67 before the phone number you want to call
Check your phone’s settings for Caller ID blocking
On iPhone, go to Settings > Phone > Show My Caller ID > turn off
On Android, open the Phone app > Settings > Calls or Calling accounts > Additional settings > Caller ID > hide number
Contact your carrier to enable permanent Caller ID blocking
Use a carrier-specific code if your provider supports one
Block Caller ID for individual calls only if permanent blocking is not available